Ultra high frequency electric discharge device and cavity resonator apparatus therefor



July 27, 1948.

E. D. MOARTHUR Filed Jan. 29, 1944 Figlf ET'AL 2,446,017 ULTRA HIGH FREQUENCY ELECTRIC DISCHARGE DEVICE AND CAVITY RESONATOR APPARATUS THEREFO Fig.2.

Inventors:

Elmer D'McArthur,

James 58:22 5,

Wavy/ 5. J

Their Attorney.

Patented July 27, 1948 2.446.017 Q i ULTRA HIGH FREQUENCYELECTRIC DIS CHARGE DEVICE AND CAVITY RESONA- i TOR APPARATUS THEREFOR. w l i :w: simian. McArthur. Schenectady, and Janeen.

Beggs, Scotia, N. Y., assignors to General Electrio Company, a corporation of New York n Application January 29, 1944, Serial No. 520,240

11 claims.

Ourinvention relates to electric discharge devices for use at; ultrahigh frequencies and, in.

particular, tosuch devices for use under condicontinuous operating period at full load It is an object of our invention to provide a new and improved high frequency electric discharge device.

tions having .a high duty. cycle or a substantially It is another object of our invention to provide a new and improved ultra-high frequency electricdischarge device suitable for use in connection With space-resonant cavities.

It isia furtherobject of our invention to provide a newand improved ultra-high frequency electric discharge device of the space-resonant type.

charge device which may be easily inserted into said cavities so thatits grid is coupled to the in- One of the features of our invention is the it employment of three telescoped and radiallytermediate conductor and. its anode and cathode, coupled respectively to the outer and inner conductors. A portion of the tube sealing means comprises; a metallic cylinder concentrically spaced from the cathode which forms therewith a portion of one ofthe space-resonant cavities.

Another feature of our invention is the provision of a cylindrical anode having a transversely receiving end which serves to remove the ultra- 30 extending portion spaced closely to its electron high frequency currents from the anode structure as shortly as possible after entering therein, the-- transverselyextending portion forming means for connecting theanodeto one of the space-resonant cavities and to separate the ultra-high frequency currents from thermal currents flowing longitudinally of the anode. Cooling means, also attached to the anode at a point near. its e1ectron..-

receiving end and wholly external of thespaceresonant cavities, providemeans for improvingthe operation of the device either under duty cycle or continuous service.

It is another object of our invention, therefore, to provide a new and improvedultra-high ire: quency electric discharge device of the space-resoi a high nant type in which division of high frequency and thermal currents flowing in the anode is made i at a point close to the electron receivingjsurface of the anode.

It is a still further object of our invention to provide a newand improved cooling meansior an;

ultra-high frequency electric discharge device'i of the space-resonanttype.

I maintain the sleeve inspacedfrelationi the; eyelet 23. In thiscompositeeathode structure;

ably embodying our invention ariqgtli'ig. 2 d 1o fiv grammatically illustrates the, electric discharge H. device of Fig. 1 as appliedto aspaceresonantffj system... f '1 ,1

Referring particularly'to rig. 1, there isfshown I 3 an ultra-high frequency; electric discharge d e"-\ vice having an madame. grid or controlielecj y trade! I, and a cathode j ljl. arranged in. 'en'd to-i l endforder. 'e; anode andeathodefare in the form of cylindrical, inen1berssubstantially axially aligned and having closedadjaeentfe in opposed closely spaced relation to fame; tron. emitting and electron receiving surfa concentrically. ;surrounding.tlie anode im is a metallic cup-shaped member 13 having a n portion ld extendingitransversely .tofthe axisof 1 the anode l0 and secured thereto, as by soldering 1 or brazing, to functionas' an-integral part. of the anode. structure. For; reasons to .bepointedbut later, the transversely. extending" wall I 4 is at: 1. tached-to the anode ,I ll asclosely as possible to; itsright-hand or electron "receiving end. .l Aninq sulating cylinder l5 concentrcially surrounding anode I0 ishermeticallysealed;at one of itsends to thetransverse wall I land has hermeticallyattached to its oppositeIendi almetallic ring Hi. The cylindrical cathode structure 12 is of the... type. disclosed in the-copending application, oi James E. Beggs serial No. 522,097, filedFebruaryj 12, 1944, andassigned to the assignee oi the pres-e entinvention. ,This cathode structure comprises 1 a plate! or disk I8 formed ofursuitable metal t suchas nick'eLandcoatedon its ,outeilor leftf hand surface witha layer lilof suitable electron emitting material, such as, for example, mixed barium and strontium e rbpnates. The disk l 8 is supported. from a metalftube ZLby means offal tubular sleeve 22 of'th in iernico foil, the latter having one of its ends welded tothe outer surface directed flange weldedbetvveen the disk I8 and a metal1iceye1et23 whichflsurroundsa tungsten heating memberor filament 24. The metal tube r 2 l, at its lefthand. end, has an inwardly extendf ing flangejfij which isjfw'elded to"a"sleeve-26 t'o' v I 3 the fernico foil '22 serves to isolate thermally the nickel disk It, heated by radiation and conduction from heater filament 24, from the metal cylinder 2! which extends outside of the enclosed region of the electric discharge device. The metal sleeve 26, formed preferably of a suitable material, such as nickel, conserves the heat of the filament by reflecting it back to the cathode surface. One end of the filament 24 is connected to a conductor 28 sealed in a disk 32 of insulatin material, such as glass, and retained within a metal sleeve 29 soldered to the inner surface-of tube 2|. The other end of the filament 24 is connected to the sleeve 29 by means of conductor 39. An additional conductor 3|, alsosealed within the glass disk 32, serves both to support and convey electric currents to one end of a suitable getter 33, the other end of the getter being supported by and electrically connected to the conductor 28. A hole 21 in metal cylinder 2!, provides communication between theenclosed region of tlieelectricdischarge, device and the getter 33 whereby finalvacuum conditions of the electron tube are established by the getter when it is flashed by current suppliedover conductors 28, 3 l.

concentrically surroundi g the composite cathode structure described-above is a, metallic sleeve34having one of its ends supported by and hermetically sealed to.a transversely. extending.

disk 35 of insulating material, such as glass, the.

disk 35 surrounding and, being hermetically sealed to the outer surface of metal tube 2|. its opposite end, the sleeve 34 has an outwardly directed fiange36 which partially. overlies and is soldered tothe metal ring lB attached to this endof J the insulating cylindenl]; Clamped, or otherwise secured between the ring i6 and the flange 36. is a metallic ring 31 which functions to support the grid ll between. the anode l and cathode I; in a desiredspaced relation with these electrodes In the composite structure thus describedthe glass cylinder 15, in conjunction with metallic members M and IS, the metal sleeve 34, and the glass disk 35 serve to su port the electrodes of the electric discharge device in alignment and to provide a sealed regionabout these electrodes. At the sametime, the metalsleeve 34 concen-v trically surrounding the left-hand end of, the cathode cylinder forms therewith a section of concentric transmission line or space-resonant cavity. The cup-shaped member I3, the metal sleeve 34, the ring [6, and the metallic tube 2! preferably are vformedof a mechanically strong conducting. material, such as jcopperorsilverplated ironand the cylinder l and disk. 35 are formedjof, a glass. having substantially the same temperature. coefficient of expansion as the metallicv members and a low high frequency dielectric loss. Onesuch glass suitable for this purpose and having the,desired characteristics contains about 45% S 1i%' K, 6% NazO, 30% BBQ- and 5% CaFz. By this construction, therefore'the electrodes l0 -l 2 are maintained in alignmentand, with substantially the. same spacing. for alloperating temperatures of the electric discharge .device..- At the same time, at ultrahigh frequencies, .namely; frequencies at which the electromagnetic waves have a wave length of the order of a few centimeters, the losses due to the dielectric materials are kept to alow value.

In order to assist in cooling the anode H1 and.

tojpermit. operation of the electric discharge device under conditions when the; duty cycle is high, that is, under conditions when the device operates for long periods of time at loads approaching full load, cooling fins 33 of suitable material, such as copper, are helically wound around the left-hand end of the anode cylinder 10 and may be integrally attached to the anode ID, as by soldering. These fins extend along the outer surface of the anode ill to a point as close as. possible to the point of connection of the By this construction of ticularly useful and advantageous separation of the ultra-high frequency currents and the thermal currents. in theanode structure is obtained.

.Thus, the. high frequency currents due to the electronsl flowing from the cathode IE to the anode I 3, because of skin effect at the ultra-high frequency at which the device is operated, fiow alongithe outer surface of the anode in to the transverse metallic connection M by means of which they may be transmitted to output circuits.

At the, same time, the thermal. currents transferring the heat generated at the electron receiving surface of the anode Hi to the exterior portion of the anode flow along the interior of the right-hand portion of the anode In to a point beyond the transverse member [4 where they are conducted to the cooling fins 38 through the good thermal contact between the left-hand portion. of the anode l0 and these fins. In this way, the

heat developed in'the anode is transmitted easily by as short a path as possible to a point external to the tube and any resonant cavities associated therewith to be dissipated either solely by the fins 38 or by a stream of air directed across the fins 38. With reference now to Fig. 2, there is shown the auxiliary or tuning space-resonant cavities which may be connected to the electric discharge device shown in Fig. 1 for resonating or tuning the circuits thereof and comprising three concentric and mutually telescoped conductors 40, 4|, 42, suitably consisting of brassor copper. The outer cylinder 40 is coupled by means of the contact ring 43 for high frequency currents to the cup-shaped metallic member l3, in turn, inteanode cavity external of the electric discharge device. Inner conductor 42 similarly has ,a plurality of spring-like fingers or contacts 45 externally contacting the outer surface of the metallic tube 2| to define, with intermediate conductor 4 i and the portion of concentric trans mission line formed bymetal tube 2| and metal cylinder 34 connected respectively to the cathode and grid, a space-resonant grid-cathode cavity.

There is also provided, in connection with the space-resonant cavities thus. defined, means for tuning or controlling the. natural resonancefrequencies of the respective cavities and this means may take the form of ,the annular plungers 41, 48 which are positionable or slidable, respectively, along the inner surfaces of the cylinders 40, 4| and the outer surfaces of the cylinders 4|, 42 being in close engagement with these cylindersin order toprevent any discontinuity in the conductive medium which definesthe cavities. The

plunger 41 may be positioned by any suitable anode-grid spaceresonant cavity by any suitable output electrode means, one form of which may be a capacity coupling defined by a metal plate 5| in spaced relation with the outer surface of the conductive tube 41' at a point of high electric field intensity. The plate 5| is connectedto a coaxial transmission line comprising aninner conductor 52 and an outer conductor 53 conductively supported from the outer surface of cylinder 40. Coupling means between the anode-grid and grid-cathode cavities is provided by the loop 54 of conductive material connected to the outer surface of cylinder 4| and extending through a slot 55 in this cylinder. This loop terminates in a plate 56 withinthe grid-cathode cavity, which plate is in spaced relation with and capacitively coupled to the cylinder 42. 1 1

Inihetelescoped cylinder arrangement thus described, the left-hand extremities of the cylinderslll), 41,42 are axially offset so as to provide a stepwise arrangementwhich is regressive as oneproceedsfrom'jthe outercylinder to the inner cylinder 42. This" is for facilitating the combination ofv these cylinders with the electric discharge device s hOWn in Fig. l and previously described; Thus, with this arrangement of telescoped cylindersearrying the, contact fingers at their ends the electric discharge device may be easily insertedinto the cavities, the contact ring 43fittingabout the'cupeshaped portion l3of the anode and being clampedtheretoby means. of a clamping ring 58. the cup shaped member I3 is pushed into the ring 43,, the spring. fingers or contacts engage the metal cylinder 34 which carries the grid oncontrol electrode of the dis-- charge device and the spring fingers 4B engage the cylindrical tube 2| of the cathode of the de vice.

Current for heatin the cathode filament may be providedby means of the transformer 60 having one of the terminals of its. secondary Winding connected to cylinder 42 andthe other. terminal of its secondary winding connected to a conductor of! concentrically supported within cylinder 42 by means of insulator 62 and terminating in a spring finger arrangement 63 which slips over the twisted ends of. conductors 28, 3|, these conductors having been twisted together after the getterl33was flashed inthe manufacture of the electric discharge device. The. electric discharge device preferably is operated with the anode at groundpotential, the cathode being maintained at high negative potential supplied thereto over a lead ll] connected to inner cylinder 42. .Potential may be supplied to the grid of the device by means of cylinder 4| and lead H connected to the end thereof, the grid potential being isolated a from the cathode potential by means of a layer or ring 12 of a suitable insulating material, such as mica, inserted in the plunger 48. The outercylinder 40, because of its direct connection with cylinder 4| through the plunger 41, is at grid potential and may be connected. to ground through a 3 grid resistance 13. i

Upon impressing a suitable unidirectional voltage between the lead 74 connected to the anode and lead "HI connected to the cathode; high frequency electromagnetic energy may be derived from the space-resonant system through the transmission line comprising conductors 52, 53.

Becausecr theboupling loop 54 and the capaci maintaining the system in a state of oscillation.

Operation or adjustment of the plungers 41, 48 controls the intensity or magnitude of the high frequency electromagnetic oscillations within the space-resonant system. The frequency of the energy derived from the space-resonant system may also be controlled by the adjustment of these plungers, which determines the natural resonance frequencies of the regions defined by the cylinders 45, 41, 42 and their associated electrodes.

When the system is to be used for amplifying of signals, input signals may be coupled into the cathode-grid cavity by any suitable coupling means such as a coaxial transmission line and a coupling loopand the cathode-gridcavity tuned tothe frequency of these signals by means of the plunger43, The intensity or magnitude of the i output signals may be controlled by means of the mediately the. ultra-high frequency currents to the space-resonant anode-grid cavity while the thermal, currents flow through the anode to the .,fins so that the anode cylinder I0 is substantially completely external to the anode-grid cavity, it i is possible to attach the thermally conductive means to the anode at a point very close to its electron receiving end and provide for more efficient and continuous loading of the electric discharge deviceat very short wave lengths.

Although, in the above-described embodiments of our invention, we have chosen to represent certain of the structural featuresas applied to a space-resonant system used .asan oscillator or amplifier, it is readily apparent that the improved structures-or systems which we provide may be applied with equal facility to space-resonant systemsused forany other purpose.

Furthermore,

i, the electron discharge device illustrated in Fig.

1. may be employed with equal facility with open transmission lines or wired circuits.

While We have shown, and described our inill}; various devices diagrammatically shown, it

will beobvious to those skilled in the art that changes and modifications may be made without departing from our invention and we, therefore,

aim to cover in the appended claims all such changes-and modifications as fall within the true spirit and scopeof our invention.

, What we claim as new and desire to secure by Letters Patent of the United Statesis:

l. A high frequency electronic discharge device comprising an anode cylinder, a cathode cylinder coaxially aligned therewith, said cylindershaving adjacent closed ends in opposed spaced relation and constituting electron emitting and electron receiving elements of said device, a transversely extending insulating disc hermetically sealed to ,versely extending portion spaced. from said closed 75 end,a cylindrical insulating member "surrounding said anode cylinder and hermetically sealed' between said transversely extending portion and said metallic cylinder, and means conductively connected to said metallic cylinder Sup orting a grid between said anode and cathode in spaced relation with said opposed ends.

A high frequency electronic discharge device comprising a cylindrical anode, a cylindrical cathode, and a grid supported in alignment, said anode having a transversely extending portion spaced longitudinally therealong from the end thereof nearer said cathode, an insulating cylinder concentrically surrounding said anode and herm tically sealed to said transversely extending portion, a metallic cylinder concentrically surrounding said cathode and having one of its ends hermetically sealed to said insulating cylinder, anda tranversely extending annular member of insulating material hermetically sealed between saidcathode and said metallic cylinder to maintain said anode and cathode in spaced relation, and means connected to said metallic cylinder and supporting said grid in alignment with said anode and said cathode.

3. A high frequency electronic discharge device comprising a cylindrical anode, a cylindrical cathode, and a grid supported in alignment, said anode having a transversely extending portion spaced longitudinally therealong from the end thereof nearer said cathode, an insulating cylinder concentrically surrounding said anode and hermetically sealed to said transversely extending portion, a metallic cylinder concentrically surrounding said cathode and having one of its ends hermetically sealed to said insulating cylinder, a transversely extending insulating disk hermetically sealed between said cathode and said metallic cylinder to maintain said anode and cathode in spaced relation, means connected to said metallic cylinder and supporting said grid in alignment with said anode and said cathode, and external cooling means connected to said anode.

l. A high frequency cavity resonator system comprising electric discharge device for use in a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end of said anode, said anode having a transversely extending portion spaced from said end, an insulating cylinder concentrically surrounding said anode and having one end hermetically sealed to said transversely extending portion, a metallic cylinder concentrically surrounding said cathode and having one of its ends hermetically sealed to said insulating cylinder, insulating means hermetically sealed between said cathode and said metallic cylinder at the other end thereof to maintain said anode and cathode in spaced relation, means conductively connected to said metallic cylinder for supporting a grid between said anode and cathode in spaced relation with said opposed ends, said cathode and said metallic cylinder providing concentric terminals for connection with a gridcathode cavity resonator, and a conductive cylinder coupled to said tranversely extending portion and providing with said metallic cylinder concentric terminals ior an anode-grid cavity resonator.

5. A high frequency cavity resonator system comprising an electric discharge device including a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end of said anode, said anode having a transversely extending portion spaced from said end, an insulating cylinder concentrically surrounding said anode and having one end hermetically sealed to'said transversely extending portion, a metallic cylinder concentrically surrounding said cathode and having one of its ends hermetically sealed to said insulating cylinder, insulating means hermetically sealed between said anode and said metallic cylinder at the other end thereof to maintain said anode and cathode in spaced relation, means conductively connected to said metallic cylinder for supporting a grid between said anode and-cathode in spaced relation with said opposed ends, said cathode and said metallic cylinder defining a-portion of a grid' cathode cavity resonator, and conductive means coupled to said tranversely extending portion and defining with said anode a portion of a cavity resonator. 1

6. A high frequency ,cavity resonator system comprising an electric discharge device including a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end of said anode, said anode having a transversely. extending portion spaced from said end, an insulating cylinder concentrically surrounding said anode and having one end hermetically sealed to said transversely extending portion, a metallic cylinder concentrically surrounding said cathode and having one of its ends hermetically sealed to said insulating cylinder, insulating means hermetically sealed between said anode and said metallic cylinder at the other end thereof and maintaining said anode and cathode in spaced relation, means conductively connected to said metallic cylinder and supporting a grid between said anode and.

cathode in spaced relation with said opposed ends, said cathode and said metallic cylinder define ing a portion of a grid-cathode cavity resonator, conductive means coupled to said transversely extending portion and defining with said anode a portion of a second cavity resonator, and cooling means for said anode lying wholly externally of said resonators and formed integrally with said anode.

7. A high frequency cavity resonator system comprising an electric discharge device having a plurality of enclosed electrodes including an anode, a cathode, and a grid, a metallic cylinder concentrically surrounding said cathode and supporting said grid, insulating means hermetically sealed between said cylinder and said cathode, an insulating cylinder hermetically sealed between said metallic cylinder and said anode, an inner, an outer, and an intermediate conductive cylinder, in telescoped relation concentrically surrounding said discharge device, said outer cylinder with said intermediate cylinder defining a grid-anode cavity resonator, said intermediate cylinder being conductively connected to said metallic cylinder, said intermediate cylinder with said inner cylinder defining a cathode-grid cavity resonator, and means for controlling the frequencies of said resonators comprising axially positionable tuning means supported between the respective cylinders.

3, A high frequency cavity resonator system comprising an electric discharge device having a plurality of enclosed electrodes including an anode, a oath-ode, and a grid, a metallic cylinder concentrically surrounding said cathode and supporting said grid, insulating means hermetically sealed between said cylinderand said anode, an

9 insulating cylinder hermetically sealed betwee said metallic cylinder and said anode, an inner, an outer, and an intermediate conductive cylinder, in telescoped relation concentrically surrounding said discharge device, said outer cylinder with said intermediate cylinder defining a grid-anode cavity resonator, said intermediate cylinder being conductively connected to said metallic cylinder, said intermediate cylinder with said inner cylinder defining a cathode-grid cavity resonator, means for controlling the frequencies 'of said resonators comprising axially positionable tuning means supported between the respective cylinders, and coupling means between said anode-grid and grid-cathode resonators.

9. A high frequency cavity resonator system comprising an electric discharge device having a plurality of enclosed electrodes including an anode, a cathode, and a grid, a metallic cylinder concentrically surrounding said cathode and supporting said grid, insulating means hermetically sealed between said cylinder and said anode, an insulating cylinder hermetically sealed between said metallic cylinder and said anode, an inner, an outer, and an intermediate conductive cylinder, in telescoped relation concentrically surrounding said discharge device, said outer cylinder with said intermediate cylinder defining a grid-anode cavity resonator, said intermediate cylinder being conductively connected to said metallic cylinder, said intermediate cylinder with said inner cylinder defining a cathode-grid cavity resonator, means for controlling the frequencies of said resonators comprising axially positionable tuning means supported between the respective cylinders, and cooling means for said anode formed integrally therewith and lying wholly external of said resonators.

10. An electric discharge device having a cylindrical anode, a cylindrical cathode, and a grid in spaced alignment, a metalic cylinder concentrically surrounding said cathode and cooperating therewith to define a portion of a cavity resonator, insulating means hermetically sealed respectively between said metallic cylinder and said anode and between said cylinder and said cathode and defining therewith a, sealed region, said grid being conductively connected to said cylinder, means external to said device and including a portion of said cylinder defining a cavity resonator between said anode and said grid, said anode being substantially completely external to said last mentioned resonator to facilitate cooling thereof.

11. An electric discharge device having a cylindrical anode, a cylindrical cathode, and a grid in spaced alignment, a metallic cylinder concentrically surrounding said cathode and cooperating therewith to define a portion of a. cavity resonator, insulating means hermetically sealed respectively between said metallic cylinder and said anode and between said cylinder and said cathode and defining therewith a sealed region, said grid being conductively connected to said cylinder, means external to said device and including a portion of said cylinder defining a cavity resonator between said anode and said grid, and thermally conductive means integral with said anode and external to said last mentioned resonator.

ELMER D. McARTl-IUR. JAMES E. BEGGS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENT Number Name Date 2,284,405 McAr-thur May 26, 1942 2,289,846 Litton July 14, 1942 2,331,193 Hutcheson Oct. 5, 1943 2,351,895 Allerding June 20, 1944 2,353,742 McAr-thur July 18, 1944 2,353,743 McAr-thur July 18, 1944 2,400,753 Haefi' May 21, 1946 2,404,113 Wagner July 16, 1946 2,408,355 Turner Sept. 24, 1946 2,408,927 Gurewitsch Oct. 8, 1946 2,409,640 Moles Oct. 22, 1946 2,411,424 Gurewitsch Nov. 19, 1946 2,427,558 Jensen et al. Sept. 16, 1947 2,427,752 Strempel et al, Sept. 23, 1947 T W U Certificate of Correction Patent No. 2,446,017. July 27, 1948.

ELMER D. MCARTHUR ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 7, lines 43 and 44, claim 4, strike out the words cavity resonator system comprising; line 45, same claim, before substantially first occurrence insert cavity resonator system comprising a;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 8th day of February, A. D. 1949.

THOMAS F. MURPHY,

Assistant O'ommz'ssz'oner of Patcnta. 1 

